package com.itcast.gateway.filter;

import org.apache.commons.lang3.StringUtils;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;

/**
 * @author zheng.zhang
 * Description 过滤器
 * @date 2020/9/8 17:55
 * Version 1.0
 */
@Component
public class SwaggerHeaderFilter extends AbstractGatewayFilterFactory {
    private static final String HEADER_NAME = "X-Forwarded-Prefix";
    private static final String URI = "/v2/api-docs";

    @Override
    public GatewayFilter apply(Object config) {
        return ((exchange, chain) -> {
            ServerHttpRequest request = exchange.getRequest();
            String path = request.getURI().getPath();
            // 判断是否直接放行
            if (!StringUtils.endsWithIgnoreCase(path, URI)) {
                return chain.filter(exchange);
            }
            // 获取新的放行规则
            String basePath = path.substring(0, path.lastIndexOf(URI));
            ServerHttpRequest newRequest = request.mutate().header(HEADER_NAME, basePath).build();
            ServerWebExchange newExchange = exchange.mutate().request(newRequest).build();
            return chain.filter(newExchange);
        });
    }
}
